This work is the only current, single volume coverage of the the latest EU energy legislation and its application on the context of the rules of the EU Treaties. Providing a comprehensive account of EU energy law following the adoption of the third energy package in 2009 this book focuses on internal market issues and the applicable rules and developments in energy law. It covers key issues such as environmental and contractual matters, and the roles and responsibilities of regulatory authorities, including the new Agency for the Cooperation of Energy Regulators (ACER). As well as the Third Package Directives in the Electricity and Gas Internal market, the work covers a wealth of other recent legislative material, including the accompanying Regulations on cross-border trade in gas and electricity, the ACER Regulation, the Regulation on Energy Market Integrity and Transparency, the Second Renewables Directive, the Gas Security of Supply Regulation, the Carbon Capture and Storage Directive, as well as proposals for the new Energy Efficiency Directive. Relevant case law from the free movement and competition fields is integrated into the substantive analysis of particular topics including detailed analysis of PreussenElektra, cases on security of supply, and various competition law decisions and cases concerning, for example, essential facilities and long-term contracts (involving capacity reservation and destination clauses etc). In addition to discussing energy contracts generally, the work also analyses regulatory problems relating to energy contracts which are not covered by other books in the field. Pre-existing long-term contracts raise problems relating to investment law (under the Energy Charter Treaty, bilateral investment treaties, etc) and fundamental rights law (property rights protection). New long-term contracts raise both regulatory and competition law questions which are also discussed. Coverage also includes the evolution of the EU's energy legislation; the liberalization of energy markets after the third package; security of supply; energy sources; and energy efficiency. It derives from a section in the looseleaf Law of the EU (Vaughan&Robertson, eds), and is made available here in a revised and expanded form for the benefit of those who do not subscribe to the looseleaf.